<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title></title>
		<style>
			/*主体内容居中*/
			
			.main {
				text-align: center;
			}
			/*使用固定定位完成两个广告模块的设置*/
			
			.ad1 {
				position: fixed;
				left: 0;
				top: 100px;
			}
			
			.ad2 {
				position: fixed;
				right: 0;
				top: 100px;
			}
		</style>
	</head>

	<body>
		<div class="nav">
			<img src="nav.png" />
		</div>
		<div class="main">
			<img src="box.png" />
		</div>
		<div class="ad1">
			<img src="r2_c1.png" />
		</div>
		<div class="ad2">
			<img src="r2_c2.png" />
		</div>
	</body>

</html>